Compound steam-turbine.



No, 756,241. PATENTEDAPR. 5, 190-4. c. v. KERR COMPOUND STEAM TURBINE.

APPLICATION FILED FEB. 24, 1903.

5 SHEETS-SHEET 1.

no Mount.

2 w m 0 NK 2 WV an C 0 w W G 9 i F Z. W a o h w M/W No. 756,241.PATENTED APR. 5, 1904. C. V. KERR.

COMPOUND STEAM TURBINE.

APPLICATION IILED FEB. 24, 1903.

N0 MODEL. 5 SHEETSSHEET 2 x FIGZ.

WITNESSES: INVENTOR ATTOR EY No. 756,241. PATENTED APR. 5, 190-4. (1'.V. KERR.

COMPOUND STEAM TURBINE.

APPLICATION FILED FEB. 24, 1903.

N0 MODEL. 5 SHEETS-SHEBT 3.

WITNES SES: v INVENTOR W C.V.Kerr

ATTORNE PATENTED' APR. 5, 1904.

C. V. KERR COMPOUND STEAM TURBINE.

AHLIUATION FILED FEB. 24, 1903.

5 SHEETS-SHEET 4.

N0 MODEL.

Fl G.4:.

y/ V I'll W No. 756,241. PATENTED APR. 5, 1904,

' c. v. KERR."

COMPOUND STEAM TURBINE,

APPLICATION FILED ran. 24, 1903. no MODEL.

5 SHEETBSHEET 51 m: uommjnns co, Puoruumq. wunmmon, a. c.

Patented. April 5, 1904.

PATENT OFFICE.

CHARLES V. KERR, RUTHERFORD, NEW JERSEY.

COMPOUND STEAM-TURBINE.

SPECIFICATION forming part of Letters Patent No. 756,241, dated April 5,1904.

Application filed February 24, 1903. Serial No. 144,799. (No model.)

To all whom, it may concern.-

Be it known that I, CHARLES V. KERR, a citizen of the United States ofAmerica, and a resident of Rutherford, in the county of Bergen and Stateof New Jersey, have invented certain new and useful Improvements inCompound Steam-Turbines, of which the following is a specification.

My object is to produce a compact steamturbine of low rotative speed andlarge horsepower. As afeature in the general arrangement and asdistinguished from vanes I employ movable buckets for receiving. theimpulse of the steam, which is delivered to them in jets throughexpansion-nozzles. The form of bucket used is of the type commonly foundin the Pelton form'of water-motor, but has special features designed toadapt it for use with steam. The nozzles used come under what is knownas expansion-nozzlesf but the steam is not expanded clear down at onestage. The movable buckets are arranged in sets, and each set isinclosed in a separate steam-tight cylinder or chamber, and the nozzlesare also likewise arranged, one group or set of nozzles for eachcylinder. Thefirst set of nozzles delivers steam-jets into the firstcylinder against a steam atmosphere having a pressure which is one stagelower than the boiler-pressure. The nozzles of the second set receivetheir supply of steam from the i first cylinder and expand it again'into a second cylinder against a second steam atmosphere of a pressureyet a stage lower, and so on through as many stages as it is desired toemploy. At the last stage the steam is expanded clear down toatmospheric pressure or pressure were converted into velocity at oneoperation in order to properly utilize it in motors of largehorse-power, the rotative' speed would be so high as to disrupt themachine by centrifugal force. By expanding the steam through successivestages I secure a lower jet velocity, which admits without loss of acorrespondingly lower bucket speed. The bucket I employ is in the formof two intersecting and partly intercommunicating cups having roundedbottoms. At the point of intersection of the two cups a wedge results,which splits each steam-jet into two independent streams and turns themback almost in an opposite direction. It is calculated that the speed ofthe'buckets shall be half that of the jets, which secures maximumefiicienc'y, and the exhaust from the buckets is stationary in respectto the casing or cylinder. The buckets'are attached to the periphery ofdisks which are secured toa common shaft passing through all thecylinders. There are several nozzles for each disk arranged in-a circlearound the same and delivering the steam-jets tangentially to thesuccession of buckets. There may be one or more bucket-bearing disks ineach cylinder, and it is preferred to increase the number of disks asthe low-pressure side is approached in order to accommodate theincreased volume of steamwithout making the buckets and nozzles solarge. Also a convenient way to increase the horse-power is simply toincrease thenumber of bucket-bearing disks and sets of nozzles for eachcylinder, other dimensions remain,- ing the same. Each set of nozzles issupplied with steam from arcshaped steam-chests,

which partly inclose each cylinder and each chests, one for eachcylinder, the first chest second set of nozzles receiving steam from thesecond chest and delivering jets to the buckets within the secondcylinder, and so on through each successive stage to the last cylinder,which has a final exhaust, each of the abovementioned sets of nozzlesbeing adapted to convert in successive operations or stages differentportions of the pressure of the steam into velocity, all of thedifference in pressure between that of any one stage and that of thenext lower being thus converted and each set of buckets being adapted toabstract all of the velocity developed at that stage, thus thesteam-pressure being alternately converted into velocity and thevelocity abstracted in stages.

My invention comprises also.certain details of construction, whichappear later in this description.

Figure 1 is a transverse section through a steam-turbine of myconstruction on the line of Fig. 2. Fig. 2 is a longitudinal section ofthe complete turbine on a vertical plane represented by the line 3/ y inFig. 1. Fig. 3 is a longitudinal section of the complete turbine on ahorizontal plane represented by the line 22 in Fig. 1. Fig. 4 is a viewof the inner side of the last or outside cylinder-head on thelowpressure side, (designated in Figs. 2 and 3by the numeral 22.) Fig. 5shows one of the steamchest casings isolated and viewed from the inside,the valve-stems beingremoved. Fig. 6is a side view of the steam-chestcasing shown in Fig. 5. Fig. 7 is atransverse section through thecentral part of one of the interior, cylinderheads. Fig. 8 is alongitudinal section of the same part shown in Fig. 7. Fig. 9 is anenlarged View of a small portion of one of the cylinders in transversesection, showing in section and relative position one of the nozzles andtwo of the buckets and showing the manner in which the nozzles and thebuckets are attached. Fig. 10 is a transverse section throughtwo of thebuckets in attached position. Fig. 11 is a front view of one of thebuckets, showing partly in section the manner of attachment to thedisks. Fig. 12 is a side sectional view of a bucket and a fragment of adisk and shows a modified form of attachment to the disks. Fig. 13 isthe same as Fig. 12, but a front view showing a fragment of disk insection.

The impulse-buckets 1, as will be noticed by the drawings, have somewhatthe form of the Pelton water-wheel bucket; but in order to adapt themfor use with steam I have devised a special form. These buckets must bevery strong and light and perfectly smooth on the inside. To this end Icontemplate drop-forging the buckets from a high grade of steel,probably nickel-steel, and the inside will be bored out perfectly smoothby a tool after the order of a milling-cutter. In order that the bucketcan be thus bored out, it is necessary that each side of the bucketthatis, each recess on either side of the dividingwedge 2-shall in contourrepresent a surface of revolution. Hence the working face of each bucketis made up of two intersecting surfaces of revolution, and the wedge 2is the resultof such intersection. The curves of the interior of thebucket in a transverse direction as they are always parts of a surfaceof revolution of course must be circles in whole or part; but the curvein the opposite or longitudinal direction may be anything desiredascircle, ellipse, hyperbola, parabola, cycloid, or a curve without aname; but I prefer about the curve shown in the drawings, which is thatof a somewhat-elongated ellipse. It is preferable to have the sharpestcurve at the bottom of each recess, because the wear from steam frictioncan be best taken care of at that point. The sides of the buckets areeither made slightly flaring, or, preferably, as shown in the drawings,the axes a a and Z) 6 of the two intersecting surfaces of revolutiondiverge slightly from each other in the direction of the mouth of thebucket.

In order to withstand the great strain, the buckets 1 must be verysecurely attached, and I prefer to dovetail them to the periphery of thedisk 5, as shown at 3. The form of these dovetails is carefullycalculated, so that the shearing strain of the head portions will equalthe breaking strain at the neck portions, thus giving the total greateststrength. In order to retain the dovetails firmly in place and addgreater strength, their contact-surfaces areelectrically weldedtogether, or else the ends of the dovetails are slightly swelled orupset, as indicated at 1; but I prefer the. weld. At 6 is shown amodified attachment of the buckets to the disks by means of rivets 7.

Each nozzle 8 has a removable tip 9, which tip is contracted to form athroat 10 and then enlarged to form an expansion-tip 11. As the steam isexpanded and converted into velocity at successive stagesin part at eachstagethe expansion-tip 11 is rather short, it being intended as nearlyas possible to secure maximum flow of steam through the nozzles. As willbe noted by the drawings, the expansiontip 11 flares outward from thethroat 10; but its walls curve, so that at the point of delivery of thejet they are parallel to each other. The nozzles 8 are attached to theinside of the cylinder-shells 12 by screw-bolts 13 passing throughannular flanges 14. Each nozzle is controlled by a manually-operatedvalve 15, which has a stem 16, whose inner end is guided by a spider 17and whose outer end passes through a gland 18, situated in thesteamchest casing 19, and terminates on the outside thereof in a handle20.

The number of stages may vary in different machines according to thevarying requirements; but the turbine shown in the drawings has sixstages, (represented by the six cylinders 21.) Each cylinder has endwalls 22 and a -or built up, as shown. One of these casings 19 is fittedto theopposite sides of each cylinder,

and each casing is made easily detachable and removable. To facilitatehandling the detached casing by means of a crane or otherwise, the eyes24 are provided. The ends of the curved steam-chest are closed by thewalls 25, i which are in one piece withthe cylinder-shell 12, and eachchest communicates with an admission-port 26.

The end walls 22 and 34 of the cylindersare cylinder ends 34 have afluid-packing surv rounding the shaft and contained in the circulargrooves 30. Within each cylinder. nave or hub pieces 31 are keyed to theshaft,- and thebucket disks are clamped between and se- -'cured to thesehub-pieces by bolts or rivets, In the cylinders which have more 1 asshown. than one bucket-disk the disks are spaced apartfrom each other onthe shaft by annular distance-blocks 32 In the turbine shownthe firsttwo cylinders have each one disk, the

following two have two disks-each, while the last two cylinders in theseries are provided each with three disks. These disks are all of 35 thesame diameter and each carries on'its pe- 1 riphery a succession of myheretofore-described specially-devised buckets.

Each cylinder has anexhaust-port 33, which is formed between the walls25 of the ends of its steam-chest, and each exhaust-port, except ofcourse the final one, opens directly into the ad mission-port belongingto the next lower stage.

The cylinder ends 22 are provided on their outside with stiffening-ribs35. The cylinder ends 34 have on either side thereof and the ends 22have on their inner sides plates 36,

spaced apart therefrom by perforated radial webs 37, the said plates andwebs being formed integral with the cylinder ends, as shown.

The webs 37 extend radially out from the center to the periphery of thecylinder ends, where they connect with the flanges 38; Each 'plate 36 isof asmaller diameter than the cylinder interiorly, so that an annularopening is left all around its edge, which opening communicates onthe.one hand with the interior of the cylinder and on'the other with thespace behind the plate between the perforated.

webs. The cylinder ends 22 and 34 have projecting portions 40 and '41and an opening 39. Inthe ends 34 the projection 40 formsa partitionbetween the different stages, and the opening 39 forms a communicationfrom" the exhaust-passage of one stage to the admission port of thenext' succeeding stage. In the ends 22 the projection 40 closes thesteam-' passages, and the opening 39 represents either the initial inletor' the final exhaust, as the case may be. At 42 is indicated theoutside walls of the exhaust and inlet passages. The passage-walls 42are secured between the opposing ends of the steam-chest casings 19 andare also secured between the edges of the cylinder-ends. It will benoticed that the cir curnference'of each cylinder is made up of threepieces, the two side pieces 12.12 and the middle piece 43, all of whichare secured together and tothe respective cylinder ends 22 and 34, andthat the ends 25 of the pieces 12 are secured between the edges of oneof the curved plates 42 and the ends of the steamchest casings 19. i

Each cylinder'is provided with'one circular row of-nozzles for eachdisk. These nozzles communicate with the steam-chest and open into thecylinder in a direction tangential to the disks and toward the mouth orworking face of the buckets. -All the nozzles and buckets are alikeexcept in size. .Both'nozzles and buckets grow progressively larger fromstage to stage from'the high toward the low pressure side. There arepreferably the same number of nozzles in each circular row; but thenumber of rows for each stage, and correspondinglythe number ofbucket-disks in each cylinder, are increased toward the low-' pressureside. The relative size, number, and proportions of the nozzles is suchthat the steam is delivered to the buckets approximately at the samevelocity in all of the cylinders. The initial-inlet passage for thesystem is indicated at 44, and the final-exhaust passage is shown at 45.At 46 is shown supports for the machine secured thereto and resting upona base 47. a

The drawings in the case are made according to calculations for amachine of ten thousand electrical horse-power, with bucket-disks eightfeet indiameter, the initial inlet pipe or passage of eight inchesdiameter, and the final exhaust thirty-six, it being intended to usesteam at two hundred pounds pressure and expand it down to about twopounds (absolute) at the final exhaust. -The' absolute pressure at eachdifferent stage would be as follows: two hundred, one hundred, fifty,twenty four, eleven, five. The working pressure available at each stagewould be represented by the difference in pressure between that stageand the next lower. With the above figures this would be represented byone hundred, fifty, twenty-six, thirteen, six, and three. In thisconnection it 'mustbe remembered that according to the laws governingthe expansion of gases when the pressure is reduced, say, one-half thevolume is doubled. By'this with scarcely no calculation it will be seenthat practically the same amount of power is available in the steam ateach successive stage indicated above. The pressure at each stage isconverted into velocity and the velocity into mechanical rotation. Eachset of nozzles, though delivering a different volume of steam,necessarily delivers the same quantity (barring loss from condensation,if any) as any one of the other sets, and all the nozzles 8 in themachine in the turbine shown are intended to deliver their jets at thesame velocity, which is calculated to be fifteen hundred feet persecond. As the bucket-disks 5 are all of the same diameter and allsecured to a common shaft 27, it is apparent that the rate of movementof all the buckets 1 must be equal, and their velocity is intended to beseven hundred and fifty feet per second or just half that of the jets.From this it is seen that the exhaust-steam issuing from the buckets lis stationary with respect to the stationary parts 12 22 25 34, &c.,of'the machine. In other words, all its kinetic energy has beenabstracted and transferred to the buckets. The nozzles 8 convert all thepressure at any one stage into velocity and the buckets abstract thatvelocity. From what has been said we see that the same number ofhorse-power is developed at each stage. Each steam-chest of the lower.and intermediate stages is virtually a common chamber with the nextpreceding cylinder. Each of these chests is supplied with exhaust-steamfrom the stage-above in the same manner that the first chest in theseries is supplied from the boiler, and the nozzles of the lower andintermediate stages use steam from their chests in precisely the samemanner that the nozzles in the first stage use boiler-steam from thefirst chest. Thus it is seen that each steam-chest acts as a reservoir,holding steam under pressure and supplying it to the nozzles as needed.

The interior parallel sides 11 of the extreme tip of the nozzle give thejet a parallel flow. This is desirable in order that all portions of thejet shall strike the bucket at the most effective angle, also in orderthat the solidity of the jet may be preserved, for if it were divergentit would have a tendency to split up and form eddies. When a jet flowsagainst the wedge in the bucket, it is gradually divided and a portionturned back along either side. Were there no wedge, the steam would havea tendency to pile upin the bottom of the bucket and to form eddies. Theprinciple here involved is the same as in the case of impulsebuckets forwater which have a dividingwedge. I I

On account of the interior of the buckets being made up of surfaces ofrevolution they can be dressed by means of revolving tools to extremesmoothness, offering very little friction to the flow of the steam. Asthe axes a a and b b of the two surfaces of revolution are slightlydivergent, the delivery sides of the buckets are caused to flareslightly outward, thus delivering the exhaust outside of the path of thefollowing bucket. As the steam escapes from the buckets it passesthrough the annular openings around the plates 36 into the space behindthese plates, where it finds its way through the holes 48 in the webs 37to the exhaust-passages 33. The manner in which the cylinder ends 22 and3 L are constructed gives not only great strength and rigidity, butprovides passages 44 for the exhaust.

As there is considerable difference in pressure between the differentcylinders 21, especially toward the high-pressure side, unless it I wereprovided against steam would leak from one cylinder 21 to another 21along the shaft 27. To guard against this, the shaft is made to fit asclosely as possible in the openings through the cylinder-heads, and alsocircular grooves 30 are provided on the inside of the openings, whichwill collect and hold water and oil, and thus provide a packing.Highpressure steam from the pipe e4 enters the admission-port 26 of thefirst steam-chest 23, is distributed to the first set of nozzles in theseries, and exhausts from the first cylinder through its port 33diametrically opposite to the inlet 26, passes through the admissionport26 of the second steam-chest 23,'through the second set of nozzles inthe series, and exhausts from the second cylinder 21 through its port 33opposite to the second admissionport 26, and so on through all of thecylinders 21, the admission and exhaust ports 26 and 33 beingalternately opposite and connecting with each other.

A proper relation or balance of pressures in the different cylinders,and consequently the proper distribution among them of the powerdeveloped, may be maintained by shutting off any desired number of thenozzles which deliver steam to any one or more of the cylinders.Condensation in the engine is reduced to a minimum by the use ofhighly-superheated steam. The interior of the machine may be readilyinspected for repairs by simply lifting ofi any one of the side sectionsof the steam-chests, including the casings 19 and 12 and nozzles andvalves altogether, thereby exposing the bucket-disks 5 throughout theirentire circumference.

By the divergence of the axes a a and Z2 6 the steam issuing from onebucket is prevented from blowing against the following bucket.

I claim as my invention- 1. In a compound steam-turbine, the combinationof a series of steam-cylinders for the several stages of expansion; aset of rotary disks within each cylinder, the disks in the successivecylinders progressively increasing in number from the high-pressurestage to the low-pressure stage of expansion; a row of buckets on theperiphery of each disk; and a set of stationary nozzles opposite eachrow of buckets and extending into said cylinders.

each cylinder and communicating therewith said sections.

2. In a compound steam-turbine, the combination of a seriesofsteam-cylinders for the several stages of expansion; a set of rotarydisks within each cylinder, the disks in the successive cylindersprogressively increasing in number from the high-pressure stage to thelow-pressure stage of expansion; a row of buckets on the periphery ofeach disk; a set of stationary nozzles opposite each row of buckets andextending into said cylinders, the end walls of said cylinders formingthe end walls of contiguous cylinders; a steam-chest for through saidnozzles; a shaft extending through all the cylinders; and exhaust-portsformed in the end walls of said cylinders and passages both forrespectively forming steam communication between any cylinder and thenext succeeding steam-chest. p

3. In a compound steam-turbine, the combination of a series ofsteam-cylinders for the several stages of expansion; a set of rotarydisks Within each cylinder, the disks in the successive cylindersprogressively increasing in number from the high-pressure stage to thelow-pressure stage of expansion; a row of buckets on the periphery ofeach disk; a set of stationary nozzles opposite each row of buckets andextending into said cylinders, the end Walls of said cylinders formingthe end Walls of contiguous cylinders; a steam-chest for each cylinderand communicating therewith through said nozzles; a shaft extendingthrough all the cylinders; and exhaust-ports I formed in the end wallsof said cylinders and passages both for respectively forming steamcommunication between any cylinder and the next succeeding steam-chest,said steam-chests being in detachable sections, and said passages beingrespectively located between the ends of 4. In a compound steam-turbine,the combination of a series of adjoining cylinders be longing to theseveral stages of expansion and containing steam at different pressures;cylinder-walls which are common to adjoining cylinders; a rotating shaftextending through all the cylinders; axial openings in saidcylinder-walls slightly larger than said shaft; annular grooves on theinterior face of said axial openings; and a fluid packing contained insaid grooves consisting of a mixture of steamor water and oil in varyingproportions.

5. In a compound steam-turbine, the com bination of a series ofadjoining cylinders; arc-shaped steam-chests in detachable sectionspartly inclosing said cylinders; stationary nozzles supported by saidsteam-chests and pro jecting into said cylinders; a rotating shaftextending through all the cylinders; a set of disks mounted on saidshaft within each cylinder, the number of disks in the set progressivelyincreasing from the high-pressure to the low-pressure cylinders; asuccession of buckets on the rim of each disk, the working face of eachbucket being formed of two intersecting surfaces of revolution and adividing wedge traversing each bucket in the plane of thesupporting-disk, the contour of said dividing-wedge being determinedbythe intersection of said surfaces of revolution,

said nozzles being disposed approximately tangential to said disks andopposite to the working face of said buckets.

6. In a compound steam-turbine, the combination of a series of cylinderscontaining steam of different and successively-decreasing pressures;rotating disks within each cylinder, the disks in the successivecylinders progressively increasing in number from the highpressure tothe low-pressure stages of expansion; buckets on the rim of each disk,said buckets being so shaped and placed as to divide a jet of steam anddeflect it in two divergent streams; arc-shaped steam chests formed indetachable sections partly inclosing said cylinders; a set of stationarynozzles for each disk supported by said steam-chests, said nozzleshaving throats terminating in a diverging mouth.

7 In a compound steam-turbine, the combination of a series ofsteam-cylinders for the several stages of expansion; a set of rotarydisks within each cylinder, the disks in the successive cylindersprogressively increasing in number from the high-pressure stage to thelow-pressure stage of expansion; a row of buckets on the periphery ofeach disk; a set of stationary nozzles opposite each row of buckets andextending into said cylinders; and valves for separately andindividually controlling said nozzles.

, 8. In a compound steam-turbine, the combination of a series ofsteam-tight cylinders, for successively containing steam of lower andlower pressures for the several stages of expansion of said steam; awall between every two cylinders; arc -shaped steam-chests; a shaftpassing through said cylinders, which are successively wider and widerin the longitudinal direction of said shaft; disks fixed to said shaftand located in said cylinders in groups, the number of disks in saidgroups progressively increasing in the successively wider and widercylinders; a row of buckets fastened on the rim of, each disk; nozzlesfor delivering steam to-said buckets and communicating between saidchests and said cylin ders; a separate valve for each nozzle, andhandles for the valves extending to the outside of said chests.

9. In a compound steam-turbine, the combination of a series of cylinderscontaining steam of successively-decreasing pressures; a

shaft passing through all the cylinders; rotat-' ing disks within eachcylinder mounted on said shaft, the number of disks in eachcylinder-progressively increasing for the lower stages of expansion; asuccession of buckets on the nm of each dlsk; arc-shaped steamchestspartly encircling each of said cylinders; stationary nozzles fordelivering steam to said buckets by communicating between said chestsand said cylinders; and dividing-Walls between the cylinders formed ofplates spaced apart by radially-diverging Webs.

10. In a compound steam-turbine, the combination of a series ofcylinders belonging to the several stages of expansion; a rotating shaftextending through all the cylinders; a set of disks Within each cylindersecured to said shaft; a series of stationary nozzles; buckets adaptedto receive jets of steam from said nozzles; dovetails projecting fromone side of said buckets; similar dovetails in the edge of each of saiddisks arranged to engage the firstnamed dovetails; and means forbringing the two sets of dovetails into close and firm contact, therebysecuring said buckets to said disks.

11. In a compound steam-turbine, the combination of a series ofcylinders for the several stages of expansion; a shaft passing throughall the cylinders; a set of rotating disks within each cylinder mountedon said shaft; a succession of buckets on the rim of each disk;arc-shaped steam-chests formed in detachable sections and partlyinclosing each of said cylinders; stationary nozzles opposite eachrotating disk, said nozzles beingsupported by said steam-chests andprojecting into said cylinders; and a valve for each nozzle, the stem ofsaid valve extending to the outside of said steam-chest.

In testimony whereof I have hereunto set my hand and seal this 20th dayof February, 1903.

CHARLES v. KERR. [11: 5.1

Witnesses:

ELIZABETH A. KERR, IRWIN J MACOMBER.

